The present invention relates to a polishing system for polishing wafers.
Conventionally, in the case of polishing surfaces of wafers, e.g., silicon wafers for semiconductor devices, the wafers have been polished by a plurality of independent machines: a sticking machine for sticking the wafers on a carrying plate; a polishing machine for polishing the wafers by pressing the carrying plate onto a polishing plate of the polishing machine and relatively moving the carrying plate with respect to the polishing plate; a peeling machine for peeling off the wafers, which have been polished, from the carrying plate; and a cleaning machine for cleaning the carrying plate from which the polished wafers have been peeled off.
Highly integrated semiconductor devices require silicon wafers which are polished with very high polishing accuracy. Such silicon wafers are made in clean rooms to remove particles in the air.
Further, large size silicon wafers are now required, so large size carrying plates are required. However, it is difficult to manually handle the large carrying plates.
Conventionally, the machines for polishing the wafers are independently installed, so the wafers are manually conveyed from one machine to another machine for each polishing step. Therefore, workers must work in the clean room for an extended time, so the degree of cleanliness of the clean room cannot be high. Furthermore accuracy of sticking the wafers on the carrying plates is also not high, so that the polishing accuracy is not high.